Automatic train control



I Sept. 22, 1931. 'r THOMAS 1,824,059

AUTOMATIC TRAIN CONTROL Filed May 13, 1925 2 Sheets-Sheet l INVENTORTHOMAS HITHOMAS BY% W ATTORNE Sept. 22, 1931. T. H. THOMAS 1,824,059

AUTOMATIC TRA IN CONTROL Filed May 13, 1925 2 Sheets-Sheet 2 INVENTOR THOMAQ H THOMAS BY%WM ATTOF'NEY Patented Sept. 22, 1931 warren STATESPATENT OFFICE THOMAS H. THOMAS, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR TOTHE WESTING- 4 HOUSE AIR BRAKE CQMPANY, OF WILMERDING, PENNSYLVANIA, ACORPORATION OF PENNSYLVANIA AUTOMATIC TRAIN CONTROL Application filedMay 13,

This invention relates to automatic train control equipments and moreparticularly to the type in which the engineer is required toacknowledge the signal indication in order to prevent the brakes frombeing applied.

The principal objectof my invention is to provide means by which theengineer is required to acknowledge successive signal indications of thesame character, such as the acknowledgement of successive occupiedblocks.

In the accompanying drawings; Fig. 1 is a diagrammatic view,partly insection, of a train control equipment embodying my invention; and Fig. 2a view similar to Fig. 1,- but with certain parts omitted, the apparatusbeing positioned as required by a caution signal indication, ifacknowledged by the engineer.

As-shown in Fig. 1 of the drawings, the equipment may comprise a brakevalvedevice 1, an acknowledging valve device 2, a caslng 3 containing aselector valve device C and a valve device D, a valve device 4, a brakeapplication valve device 5, a main reservoir 6, two stop reservoirs 7and 8, an acknowledging reservoir 9, and a timing reservoir 16.

The brake valve device may comprlse a casing having a rotary valvechamber 11 and containing a rotary valve 11 which is connected by a keymember 12 to the operatlng handle 13. Disposed in the casing at one sideof the key member 12 is a check valve 14 subject on one sideto thepressure of a spring 15. A cam 16, carried by the key memier 12, isadapted to engage and hold the check valve 14 unseated in release,running, and holding positions of the brake valve device, the checkvalve being allowed to seat in all other positions of the brake valve.

The acknowledging valve device 2 may comprise a casing having a chamber17 containing a rotary valve 18, which is operatively connected to anoperating handle 19. Fluid under pressure from the main reservoir assupplied through pipes 21 and 22 and pasand the pressure exerted by acoil spring 20, act to hold the rotary valve 18 to its seat at alltimes.

The selector valve device C contained in the 1925. Serial No. 29,951.

casing 3 may comprise a piston 26 contained in piston chamber 24, whichis connected to a volume chamber 25, and a slide valve 27 contained in avalve chamber 28 and adapted to be operated by the pisto1126. The valvedevice D also contained in the casing 3 may comprise a flexiblediaphragm 31 contained in diaphragm chamber 32 and subject on one sideto fluid pressure and on the other side to the pressure of a coil spring33, said diaphragm being adapted to operate double beat valves 34 and 35contained in valve chamber 36. Attached to the casing 3 is a magnet '37,which is adapted tooperate double beat valves 38 and 39 for controllingthe supply and exhaust of fluid under pressure to and from the pistonchamber 24 of the selector valve device D.

The valve device 4 may comprise a casing in which is contained a timingvalve device E i and an acknowledging pilot valve device F. The timingvalve device E may comprise a flexible diaphragm 41 contained indiaphragm chamber 41 and subject on one side to the pressure of fluid inthe timing reservoir 10 and on the opposite side to the pressure of acoil spring 42. The diaphragm 41 is adapted to operate double beatvalves 43 and 44, which are contained in valve chamber 45.

The acknowledging pilot valve device may comprise a piston 46 containedin a piston chamber 47, a valve piston 48 contained in a valve chamber49, and a valve 50 contained in valve chamber 51, said valve piston 48and valve 50 being operable by the piston 46. Associated with the casingof valve device 4 is a magnet 52, which is adapted to operate doublebeat valves 53 and 54 for controlling the supply and exhaust of fluid toand from diaphragm chamber 41 of the timing valve device E and diaphragmchamber 32 of the valve device D. i For the purposes of the presentinvention, the brake application valve device 5 is shown as comprising acasing having a piston chamber 55 containing a piston 56 and a valvechamber 57 containing a slide valve 58, the slide valve being operablebythe piston 56. A coil spring 59 is interposed between the casing and theouter face of piston 56 to maintain said piston in its innermostposition, when the pressures of fluid on opposite sides of said pistonare equal.

Before explaining the operation of the apparatus described, it should bepointed out that trackway apparatus and train carried governingapparatus is provided and so operates that when a train enters or isproceeding in a clear block the magnet 52 will be energized and themagnet 37 deenergized, in acaution block the magnet 52 will bedeenergized and magnet 37 energized, and in an occupied block both ofsaid magnets will be deenergized.

In operation, fluid under pressure from. the main reservoir 6 flowsthrough pipes 21 and 60 to rotary valve chamber 11 of the brake valvedevice 1, also through pipes 21 and 22, cav ity 61 in rotary valve 18 ofthe acknowledging valve device 2, and thence through passage and pipe 62to the acknowledging reservoir 9, charging the same. Fluid from the mainreservoir is al o supplied through pipe 21a-nd passage 63 to valvechamber 57 of the brake application valve device, from whence it flowsthrough a restricted port 64, in piston 56, to piston chamber 55, andassuming that communication is closed so that fluid cannot be ventedthrough passage 84, the fluid pressures on opposite sides of said pistonwill equalize, so to permit the spring 59 to shift the piston 56 to itsinnermost position.

Fluid under pressure from the main reservoir is also supplied throughpipes 21 and 30 and passage 29 to valve chamber 28 of the selector valvedevice G. A passage 65 leading from passage 29 suppies fluid to one sideof the magnet controlled double beat valve 39. Fluid is also suppliedfrom pipe 30 through passage 66 to valve chamber 51 of the acknowledgingpilot valve device and to one side-of the magnet controlled double beatvalve 54. V 45 Assuming'the train is running in a clear block, themagnet 52 will be energized and the magnet 37 deenergized. The magnet 52being energized will cause the double beat valve 53 to be seated and'thevalve 54 to be unseated, as is clearly shown in Fig. 1 of'the drawings.

The double beat valve being unsealed, fluid under pressure from the mainreservoir, which is always present at one side of said valve, will besupplied through passage 67 to diaphragm chamber 41 of the timingvalvedevice E, thence through pipe 68 to the timing reservoir 10, chargingthe same. The fluid under pressure supplied to diaphragm chamber '41acts to move the diaphragm 41, J0 so as to seat the double beat valve 44and unseat valve 43. A passage and pipe 69 is connected to passage 67-so that fluid is also supplied to diaphragm chamber 32 of valve deviceD, moving the diaphragm 31 so as to 6 seatdouble beat valve 34 andunseat valve 35.

In a clear block, the magnet 37 is deenergized so that the double beatvalve 39 will be seated and the valve 38 unseated to Connect the pistonchamber 24, and consequently the volume chamber 25 of the selector valvev0 device C, toatmosphere by way of passage 7 0 past unseated valve 38and choked passage 71. The pressure of fluid in valve chamber 28 actingon the opposite side of the piston'26 will then shift said piston andconsequently slide valve 27 to a position in which the stop. reservoir 8is'connected to atmosphere,through pipe and passage 72, cavity 73inslide valve 27, passage 74, valve chamber 36 and atmospheric exhaustport 75. In this position of slide valve 27, the stop reservoir 7 isconnected to atmosphere, through pipe and passage 76, cavity 77 in slidevalve 27, passage and pipe 78, valve chamber 49, passage 80, valvechamber 45, past unseated valve 43 to the atmospheric exhaust port 81.

Vhen the train proceedsfrom a clear block into a, caution block, ashereinbefore ex plained, the magnet 52 will be deenergized and themagnet 37 will be energized. The deenergization of the magnet 52 causesthe valve 54 to seat and valve 53 to be unseated.

The unseating of valve 53 connects the passage 67 and consequently thediaphragm chamber 32 of the valve device D, the diaphragm chamber 41 ofthe timing valve device and the timing reservoir 10 to atmosphere, pastunseated valve 53 and through atmospheric exhaust port 82. The volume ofthe timing reservoir 10 and the area of the exhaust port 82 are suchthat a predeter mined time interval, such for example as 4 seconds, willelapse before the fluid pressure is reduced sufliciently to permit thediaphragm 41 of the timing valve device to 105 move. This time intervalis provided to give the engineer sufficient time to acknowledge thesignal indication and thereby prevent a brakeapplication, as will behereinafter described.

The energization of magnet 37 causes the double beat valve '38 to beseated and the valve 39 to be unseated, so as to supply fluid underpressure from the main reservoir, which is always present at one side ofthe 115 valve 39, through passage 70 to piston chamber 24 and volumechamber 25 of the selector valve device C. The fluid under pressuresupplied to piston chamber 24, together with the pressure exerted byspring 26*, shifts the 120 piston 26 to its innermost position, movingthe slide valve 27 to a position in which the stop reservoir 8 isconnected to valve chamber 45 of the timing valve device, through pipeand passage 72, cavity 77 in slide valve 27, passage and pipe 78, valvechamber 49 and passage 80. The stop reservoir 7 is connccted, in thisposition of slide valve 27, to atmosphere by way of pipe and pasasge 76,

cavity 94 and atmospheric exhaust port 95. I30

If the signal indication has not been acknowledged at the expiration ofthe predetermined time interval, the reduced pressure in diaphragmchamber 41 of the timing valve device will permit the spring 42 actingon the opposite side of the diaphragm 41 to move said diaphragm so as toseat double beat valve 43 and unseat valve 44, thereby connecting thepiston chamber 55 of the brake application valve device, through passageand pipe 84 and past unseated valve 44 to valve chamber 45 andconsequently to stop reservoir 8. 1 I

The venting of fluid under pressure from piston chamber to the stopreservoir 8 permits the greater pressure in valve chamber 57, acting onthe opposite side of the piston 56 to shift said piston to its outermostposition with a consequent movement of the slide valve 58 to a positionin-which the brake pipe is Vented to atmosphere, through pipe andpassage 86, cavity 87, in

slide valve 58 to atmospheric exhaust port 88, thereby causing anapplication of the brakes throughout the train.

- The engineer may prevent a brake application from being caused asabove described by moving the operating handle .19 and consequently therotary valve 18, of the acknowledging valve device, to the positionshown in Fig. 2 of the drawings, provided the engineer acts before theexpiration of the predetermined time interval, hereinbefore referred to.in this position of the rotary valve 18, fluid unden pressure from theacknowledging reservoir 9 is supplied to piston chamber 47, of theacknowledging pilot valve device, through pipe and passage 62 cavity inrotary valve 18, passage and pipe 91, cavity 92 in slide valve 58 andpassage and pipe 93.

The fluid so supplied acts to shift the piston 46 to its innermostposition with a consequent movement of the valve piston .48 and valve 50to the position shown in Fig. 2 of the drawings. In this position ofvalve pis ton 48 communication between passage 7 Sand passage 80 is cutoil, and consequently communication from piston chamber 55 of the brakeapplication valve device to stop reser voir 8 is out oh and at the sametime fluid under pressure from the main reservoir, which is alwayspresent in valve chamber 51, is supplied past unseat-ed valve throughvalve chamber 49, passage and pipe 78, cavity 77 in slide valve 27 andpassage and pipe 72 to stop reservoir 8, charging the same.

In the acknowledging position of rotary valve 18, of the acknowledgingvalve device 2, fluid from the acknowledging reservoir 9 is slowlyvented to atmosphere, through a branch of passage 93 containing a choke,so that after a predetermined time interval the pressure of fluid insaid reservoir and consequently in piston chamber 47 of acknowledgingpilot valve device, will be reduced sufliciently to permit the higherpressure in valve chamber 49 to shift the piston 46 and consequently thevalve piston 48 and valve 50 to their former position connectingpassages 78 and 80 and cutting olf fluid from valve chamber 51, as shownin Fig. 1 of the drawings. However, the stop reservoir 8 having beencharged from valve chamber 51, as here inbefore described, fluidfrom'piston chamber 55 will not be Vented to said reservoir, with theresult that the piston 56 and slide valve 58 will be maintained innormal release position, and a brake application will be prevented. I

When the train passes from a caution block into an occupied block, thetrack circuits are such that the magnet 52 will remain deenergized, asin a caution block, and the magnet 37 will become deenergized. Themagnet 52 remaining deenergized will cause the timing valve device E andthe valve device D to remain in the positions shownin Fig. 2 of thedrawings.

The deenergization of magnet 37 will cause the double beat valve 39 tobeseated and valve 38 to be unseated so as to connect piston cham ber 24and volume chamber 25 to atmosphere by way of passage 70, past unseate-dvalve 38, and choked passage 71. The volumes of piston chamber 24 andchamber 25 are so related with respect to choked passage 71, that apredetermined time interval, such for example as 4 seconds, will elapsebefore the pressure of fluid in piston chamber 24 will be reducedsufficiently to permit the pressure of fluid in valve chamber 28, whichacts on the opposite sideof the piston 26, to shift said piston to itsoutermost position.

If the change in signal indication is acknowledged by the engineerbefore the eX- piration of the predetermined time limit, the apparatuswill operate, as hereinbefore described, to prevent a brake application,so that the trainmay proceed into the occupied block. V r

If the change in the signal indication is not acknowledged before theexpiration of'the time limit, the piston 26 will be shifted to itsoutermost position, with a consequent movement of slide valve 27 to aposition so as to connect the stop reservoir 7 to piston chamber 55 ofthe brake application valve device, through pipe and passage 76, cavity77, passage and pipe 78, valve chamber 49, passage 80, past unseatedvalve 44, and through passage and pipe 84. Fluid from the piston chamber55 will then be vented to the reset voir 7 and a brake applicationeii'ected as hereinbefore described.

The apparatus as so far described requires acknowledgement in order toprevent a brake application upon entering an occupied block. but if thetrain proceeds from one occupied block to a succeeding occupied block,since the signal indication does not change, there will be no action ofthe apparatus and consequently the engineer will not be required toacknowledge successive occupied blocks. In order to requireacknowledgement of successive occupied blocks, a special circuit shouldbe provided which extends a predetermined distance in advance of thebeginning of each block, and which operates in conjunction with theusual track circuits, to give a caution indication, while the train ispassing over said loop, but only when the next succeeding block isoccupied.

A loop circuit of the above character is shown in Patent No. 1,492,719of R. A. Mc- Cann, dated May 6, 1924, and the desired functioning willbe obtained by substituting the magnet 37 of the present constructionfor the magnet M of the patent.

The caution indication acts to energize the magnet 37 and cause theselector valve device C to be shifted to the position shown in Fig. 2 ofthe drawings in which the stop reservoir 7 is connected to atmosphere by'way of pipe and passage 76, cavity 94 in slide valve 27 and atmosphericexhaust port When the train new enters the occupied block, the magnet 37will be deenergized, which acts to connect the piston chamber 24 of theselector valve device C to atmosphere and thereby permit the pressure offluid in valve chamber 28 to shift the piston 26 and consequently slidevalve 27 to the position shown in Fig. 1 of the drawings. In thisposition of slide valve 27 the stop reservoir 7 is connected to pistonchamber 55 of the brake application valve device, and if the signalindication has not been acknowledged, fluid therefrom w ll be vented tothe reservoir 7 and a brake application.

effected. It will be evident that if the indication is acknowledgedwithin the predetermined time interval that a brake application will beprevented, as hereinbefore described.

With the brake valve device 1 in running position when a brakeapplication is effected by movement of the brake application valvedevice to application position, a connection from piston chamber 55 toatmosphere is made through passage 84, cavity 97 in slide valve 58,passage and pipe 98, past unseated valve 14 and through atmosphericexhaust port 99. r

In order to release the brakes, the handle 13 of the brake valve deviceis moved to lap position, in which the cam 16 moves away from the stemof valve 14, permitting the spring 15 to seat said valve. 'The seatingof valve 14 cuts ofl the connection from piston chamber 55 of the brakeapplication valve device to atmosphere, which connection was effected,through passage 84, cavity 97 in slide valve 58, passage and pipe 98,past unseated valve 14 and atmospheric exhaust port 99, by movement ofthe brake application valve device to application position.

The atmospheric connection just described being cut off by movementofthe brake valve handle to lap position, fluid from valve chamber 57 ofthe brake application valve device, equalizes through restricted port 64in piston 56 so that spring 59 will shift said piston and slide valve 58to release position. After suflicient time has elapsed to permit thebrake application valve device to be shifted to release position, thehandle'13 of the brake valve device is moved to release position, inwhich the brake pipe pressure is built up in the usual way, so as toeffect the release of the brakes throughout the train.

The valve device D is provided in order to make it unnecessary for theengineman to acknowledge the signal indication, when the train ispassing from an occupied block to a caution block. The diaphragm chamber32 of said valve device will be at atmospheric pressure, while operatingin an occupied block, due to the connection through pipe and passage 69,passage 67, pastunseated valve 53 and through atmospheric exhaust port82.-

The diaphragm chamber 32 being at atmospheric pressure will permit thespring 33 to move the diaphragm 31 so to seat valve 35 and unseat valve34. Since the magnet 37 is deenergized in an occupied block, theselector valve device will be in the position shown in Fig. 1 of thedrawings, and consequently the stop reservoir 8 is charged from thevalve chamber 28 of the selector valve device C, through passage 100,past unseated valve 34, passage 74, cavity 73 in slide valve27 and pipeand passage 72.

If the train proceeds from an occupied block to a caution block, themagnet 37 is energized ihereby and acts to shift the selector valvedevice C to the position shown in Fig. 2 of the drawings, so as toconnect the stop reservoir 8 to piston chamber 55 of the brakeapplication valve device, but said reservoir being already charged withfluid under pressure, fluid will not be vented from the applicationvalve device and consequently it will not be necessary for the engineerto acknowledge under the above condition.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. In a train control apparatus, the combination with a fluid pressurecontrolled brake application means operated upon a reduction in fluidpressure for effecting an application of the brakes, oftwo reservoirs,valve means having one position in which one reservoir is connected to apassage through which fluid is vented from said brake application meansto said reservoir and another position in which said reservoir isconnected to the atmosphere and the other reservoir is connected to saidpassage so that fluid is vented from said application means to the lastmentioned reservo and means controlled according to the si idication forcontrolling the operation oi. said valve means.

2. in a train control apparatus, the combination with a fluid pressurecontrolled brake application means, of two reservoirs, valve meanshaving two positions, in each of which I one of said reservoirs isconnected to a passage through which said brake application means iscontrolled, and signal indication controlled means for controlling thesupply and exhaust of fluid under pressure to and from one reservoir inone position of said valve means in which communication from saidreservoir through said passage to said brake application means is cutoff.

3. In a train control apparatus, the combination with two reservoirs, ofa fluid pressure brake application means operated upon the venting offluid from said means to either reservoir for effecting an applicationof the brakes, means controlled by a change in the signal indication forconnecting one or the other of said reservoirs to said brake applicationmeans, and means operable by the engineer for controlling communicationthrough which said reservoirs are connected to said brake applicationsmeans.

4. In a train control apparatus, the combination with two reservoirs, ofa fluid pressure controlled brake application means, valve meansoperated upon the venting of fluid from said means to either reservoirfor effecting an application ofthebrakes and controlled by a. change inthe signal indication for connecting one or the other of said reservoirsto said brake application means, means controlled according to thesignal indication for supplying and releasing fluid to and from onereservoir in one position of said valve means, and means operable by theengineer for controlling the supply of fluid t0 the other reservoir.

5. In a train control apparatus, the combi nation with a fluid pressurecontrolled brake application means, of two reservoirs, fluid pressureoperated valve means having positions for connecting one or the other ofsaid reservoirs to said brake application means, and means controlledaccording to the signal indication for varying the fluid pressure onsaid valve means to operate said valve means.

6. In a train control apparatus, the combination with a reservoir, of afluid pressure controlled brake application means, and means operatingunder a danger signal indication for establishing a communicationthrough which fluid under pressure is supplied to said reservoir andunder a caution signal indication for venting fluid under pressure fromsaid brake application means to said reservoir.

7. In a train control apparatus, the commy hand.

THOMAS H. THOMAS.

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